Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>IR spectroscopy from three epochs is presented for the very bright, X-ray nova YZ Reticuli (Nova Reticuli 2020). The first spectrum, from 2.5 months after outburst, shows a nova well into the coronal phase, with strong lines of [Si <jats:sc>vi</jats:sc>] and [Si <jats:sc>vii</jats:sc>], and with little or no interstellar reddening, and no dust emission. The second spectrum, from one month later, shows a four-fold drop in brightness and a measurable increase in the coronal lines relative to the lower excitation features. The final spectrum, from 7 months post outburst, is a factor of six fainter and shows a decrease in the relative strength of the coronal lines from the previous epoch. Emission lines from O <jats:sc>i</jats:sc> and [N <jats:sc>i</jats:sc>] are present at all epochs, indicating the persistence of a region of largely neutral gas in this otherwise high excitation object.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Between 2015 September and 2016 January, we obtained 18 spectra of the 2015 classical outburst of AG Pegasi—a symbiotic star consisting of a white dwarf (WD), red giant, and surrounding nebula. Modelling the flux contributions of these components reveals that nebular emission, from the reprocessing of high energy WD photons, dominates the 3200–6300 Å range. Nebular emission rises and falls in line with changes seen in the WD, whose properties have been derived using H<jats:italic>β</jats:italic> and He <jats:sc>ii</jats:sc> (4686 A) line flux, and emission measure calculations. WD parameters follow changes seen in visual band light curves. During the second peak of the outburst, WD temperatures reach 166,000 ± 6000 K, with a luminosity and radius of 14,000 ± 2000 <jats:italic>L</jats:italic> <jats:sub>⊙</jats:sub> and 0.149 ± 0.014 <jats:italic>R</jats:italic> <jats:sub>⊙</jats:sub> respectively. These features are consistent with an expansion of the WD pseudo-photosphere due to an accretion rate exceeding that required for stable hydrogen burning.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present the results of our spectroscopic surveys of members of two nearby, rich open clusters, Praesepe and the Hyades, which fold in updated membership catalogs for both based on Gaia data. Our data include 1200 of our own <jats:italic>R</jats:italic> ≈ 2000 spectra (900 for Praesepe, 300 for the Hyades), 300 archival spectra (270 for Praesepe, 30 for the Hyades), and more than 1000 spectra obtained by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (750 for Praesepe and 440 for the Hyades). For each good-quality spectrum, we measure the H<jats:italic>α</jats:italic> equivalent width and run a Monte Carlo iterator to estimate the uncertainty. Our surveys include at least one spectrum for 870 stars in Praesepe and for 460 stars in the Hyades. The vast majority of these are stars later than F7 (&lt;1.2 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>). Our coverage extends down to a spectral type of M6 (≈0.2 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) in both clusters, allowing us to compare in detail the equivalent-width distributions for these two coeval populations (≈800 Myr). Our surveys represent the most extensive investigations of H<jats:italic>α</jats:italic> emission in single-aged low-mass stellar populations to date, and form the basis of our exploration of the age-rotation-activity in these two benchmark clusters.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a new analysis of the light curve of the young planet-hosting star TOI 451 in the light of new observations from TESS Cycle 3. Our joint analysis of the transits of all three planets, using all available TESS data, results in an improved ephemeris for TOI 451 b and TOI 451 c, which will help to plan follow-up observations. The updated mid-transit times are BJD–2,457,000 = <jats:inline-formula> <jats:tex-math> <?CDATA ${1410.9896}_{-0.0029}^{+0.0032}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1410.9896</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.0029</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.0032</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> , <jats:inline-formula> <jats:tex-math> <?CDATA ${1411.7982}_{-0.0020}^{+0.0022}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1411.7982</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.0020</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.0022</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, and <jats:inline-formula> <jats:tex-math> <?CDATA ${1416.63407}_{-0.00100}^{+0.00096}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1416.63407</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.00100</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.00096</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> for TOI 451 b, c, and d, respectively, and the periods are <jats:inline-formula> <jats:tex-math> <?CDATA ${1.8587028}_{-10e-06}^{+08e-06}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1.8587028</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>10</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>06</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>08</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>06</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math> <?CDATA ${9.192453}_{-3.3e-05}^{+4.1e-05}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>9.192453</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.3</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>05</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.1</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>05</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> , and <jats:inline-formula> <jats:tex-math> <?CDATA ${16.364932}_{-3.5e-05}^{+3.6e-05}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>16.364932</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.5</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>05</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>3.6</mml:mn> <mml:mi>e</mml:mi> <mml:mo>−</mml:mo> <mml:mn>05</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasabef70ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> days. We also model the out-of-transit light curve using a Gaussian Process with a quasi-periodic kernel, and infer a change in the properties of the active regions on the surface of TOI 451 between TESS Cycles 1 and 3.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>As part of a search for X-ray emission from RV Tau variable stars, we discovered a serendipitous X-ray detection of the closest RV Tau variable star, HD 143352. X-rays were detected in the 0.2–2.0 keV energy band, with most counts detected in the 0.5–1.0 keV band. The emission is consistent with a 10<jats:sup>6</jats:sup> K plasma and <jats:italic>L</jats:italic> <jats:sub>X</jats:sub> ∼ 2 × 10<jats:sup>28</jats:sup> erg s<jats:sup>−1</jats:sup>. This would be the second RV Tau star detected in X-ray emission. However, after estimating the temperature (<jats:italic>T</jats:italic> <jats:sub>eff</jats:sub> ∼ 6000 K) and bolometric luminosity (<jats:italic>L</jats:italic> <jats:sub>bol</jats:sub> ∼ 4<jats:italic>L</jats:italic> <jats:sub>⊙</jats:sub>) from the spectral energy distribution, we place HD 143352 on the main sequence. These stellar parameters suggest HD 143352 is neither an RV Tau variable nor a post-asymptotic giant branch star nor a super giant, but rather an early F-type main sequence star. The X-ray emission detected from HD 143352 is consistent with coronal-like emission with <jats:italic>L</jats:italic> <jats:sub>X</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>bol</jats:sub> ∼ 10<jats:sup>−6</jats:sup>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>E+A galaxies are post-starburst galaxies that have undergone a recent, complete quenching of star formation. We have analyzed a color-constrained sample of galaxies from the Sloan Digital Sky Survey within a 77.′5 radius of the center of the Leo cluster of galaxies (A1367; J2000 11:44:36.5 + 19:45:32) within 3000 km s<jats:sup>−1</jats:sup> of Leo’s redshift of <jats:italic>z</jats:italic> = 0.022 to identify and survey the E+A galaxy candidates in the cluster. Within this sample, we classified 52 of these galaxies as E+A galaxy candidates based on their spectral shapes, <jats:italic>u</jats:italic>–<jats:italic>r</jats:italic> color, lack of H<jats:italic>α</jats:italic> emission, and higher-order hydrogen Balmer absorption. We further subdivide this group into “blue” and “green” E+A candidates. Our results show that the E+A galaxy candidates are distributed across the northwest and southeast subclusters of Leo, possibly as a result of merging between the two subclusters.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The abundances of several elements in the atmosphere of the HgMn star 14 Sge (HR 7664) are derived from the analysis of high-resolution spectra obtained recently with the spectropolarimeter NeoNarval. A large phosphorus overabundance, about 60 times the solar abundance, is found. This study is the beginning of a systematic survey of all northern HgMn stars aiming at deriving their abundances in a consistent manner.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>With this research note, we are releasing the CARMA-NRO Orion Survey data first presented in Kong et al., enhanced with additional coverage of the L1641-C region to the south of the integral-shaped filament. We are including position–position–velocity cubes for the molecular lines <jats:sup>12</jats:sup>CO(1–0), <jats:sup>13</jats:sup>CO(1–0), and C<jats:sup>18</jats:sup>O(1–0). The original paper includes details of the data reduction and final sensitivity. The mapped region now spans about 2.°5 along the Orion A cloud in the north–south direction, providing an unprecedented overview of the extended molecular gas. The associated data cubes are publicly available on the Harvard Dataverse <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://doi.org/10.7910/DVN/6Q26PN" xlink:type="simple">10.7910/DVN/6Q26PN</jats:ext-link> (Version 3). Kong et al. and this research note should be cited when using these data.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The W-CDF-S and ELAIS-S1 fields will be two of the LSST Deep Drilling fields, but the availability of spectroscopic redshifts within these two fields is still limited on deg<jats:sup>2</jats:sup> scales. To prepare for future science, we use <jats:monospace>EAZY</jats:monospace> to estimate photometric redshifts (photo-<jats:italic>z</jats:italic>s) in these two fields based on forced-photometry catalogs. Our photo-<jats:italic>z</jats:italic> catalog consists of ∼0.8 million sources covering 4.9 deg<jats:sup>2</jats:sup> in W-CDF-S and ∼0.8 million sources covering 3.4 deg<jats:sup>2</jats:sup> in ELAIS-S1, among which there are ∼0.6 (W-CDF-S) and ∼0.4 (ELAIS-S1) million sources having signal-to-noise ratio (S/N) &gt;5 detections in more than 5 bands. By comparing photo-<jats:italic>z</jats:italic>s and available spectroscopic redshifts, we demonstrate the general reliability of our photo-<jats:italic>z</jats:italic> measurements. Our photo-<jats:italic>z</jats:italic> catalog is publicly available at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://doi.org/10.5281/zenodo.46031780" xlink:type="simple">10.5281/zenodo.46031780</jats:ext-link> </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We summarize new results for the locations of the satellites of isolated host galaxies that were presented at the 237th meeting of the American Astronomical Society. Using 3575 host-satellite systems, we investigated the spatial distributions of the satellites with respect to their hosts using a Mean Resultant Length (MRL) statistic. In agreement with a previous analysis that relied on a less optimal statistic, we find that the satellites of isolated blue hosts have a strong tendency (&gt;99.9999% confidence level) to be clustered toward one direction relative to their host. This also holds true for the full sample, but is driven by the “lopsidedness” of the satellite distributions around blue hosts. For red hosts (which comprise 76% of the sample), the MRL indicates only a marginal degree of lopsidedness (98.5% confidence level) in the satellite locations.</jats:p>